What is a good base saturation?
Base Saturation for soils to be productive must be greater than 80%. A soil that has a Base Saturation of less than 40% will develop problems and it will be difficult for this field to produce a crop.
How do you calculate base saturation?
To calculate the percent base saturation, divide the sum of the K, Mg, Ca, and Na (the bases) in meq/100g soil by the CEC (all these values were calculated above). Multiply the result by 100%. Example: K = 0.28 meq/100g soil.
What does base saturation measure?
Base saturation indicates the balance between acid and base cations adsorbed by the cation exchange complex (CEC) of a soil. The term is a partial misnomer because a base is a chemical compound that can react with an acid to form a salt; calcium hydroxide, Ca(OH) 2, is an appropriate example.
What is a good CEC?
Organic matter has a very high CEC ranging from 250 to 400 meq/100 g (Moore 1998). Because a higher CEC usually indicates more clay and organic matter is present in the soil, high CEC soils generally have greater water holding capacity than low CEC soils.
What is a high base saturation in soil?
Base saturation is calculated as the percentage of CEC occupied by base cations. Figure 2 shows two soils with the same CEC, but the soil on the right has more base cations (in blue). Therefore, it has a higher base saturation.
Is a high CEC good?
When a high CEC soil has good test levels, it offers a large nutrient reserve. However, when it is poor, it can take a large amount of fertilizer or lime to correct that soil test. A high CEC soil requires a higher soil cation level, or soil test, to provide adequate crop nutrition.
What is base saturation and exchangeable sodium percentage?
The acceptable base saturation limit for sodium is 15%. This is also called the Exchangeable Sodium Percent or ESP. Sodium levels higher than 15% on the exchange site could result in soil dispersion, poor water infiltration, and possible sodium toxi city to plants.
What does base saturation of soil mean?
Base saturation is the sum of base cations (Ca2+, Mg2+, K+, and Na+) held onto the soil exchange sites divided by the total CEC and expressed as a percentage. Advocates of the BCSR maintain that there is an approximate ratio of basic cations that must occupy the soil CEC or plant growth will be limited.
What is base saturation of a soil?
Base saturation is calculated as the percentage of CEC occupied by base cations. Figure 2 shows two soils with the same CEC, but the soil on the right has more base cations (in blue). Therefore, it has a higher base saturation. Base saturation is closely related to pH; as base saturation increases, pH increases.
What is the importance of base saturation?
Base saturations show the concentration of cations on the soil colloid. It’s important to ask how complete these numbers are. If the tests include sodium and other bases along with calcium, magnesium and potassium, these numbers will be added to calcium and magnesium numbers, falsely elevating them.
Why is base saturation important?
Soils with high percent base saturation have a higher pH; therefore, they are more buffered against acid cations from plant roots and soil processes that acidify the soil (nitrification, acid rain, etc.). They contain greater amounts of the essential plant nutrient cations K+, Ca2+ and Mg2+ for use by plants.
What is a low CEC?
If the CEC number is low, not many molecules are able to bind (react) to the particle surface. If the number is high, a larger number of molecules can bind to the particle’s surface. High sand soils have low CEC values with the number increasing as the soil contains more clay, silt and organic matter.
How to calculate the percentage of base saturation?
The percentage base saturation is expressed as follows: %BS = [ (Ca2+ + Mg2+ + K+)/CEC] × 100 Depending on soil pH, the soil’s base saturation may be a fraction of CEC or approximately equal to CEC. In general, if the soil pH is below 7, the base saturation is less than CEC.
How are base cation saturation ratios used in BCSR?
In the BCSR system, soil cations are balanced according to varying ratios often stated as giving ‘ideal’ or ‘balanced’ soil. These ratios can be between individual cations, such as the calcium to magnesium ratio, or they may be expressed as a percentage saturation of the cation exchange capacity (CEC) of the soil.
What happens to base saturation as pH increases?
The %BS increases with increasing soil pH ( Figure 5 ). The availability of Ca 2+, Mg 2+, and K + increases with increasing %BS. For example, an 80% BS soil provides cations to plants more easily than 40% BS soil.
Why is base saturation important for plant growth?
Soils with high percent base saturation have a higher pH; therefore, they are more buffered against acid cations from plant roots and soil processes that acidify the soil (nitrification, acid rain, etc.). They contain greater amounts of the essential plant nutrient cations K +, Ca 2+ and Mg 2+ for use by plants.